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21 <!-- $Id: lwres_gnba.docbook,v 1.4.206.3 2005/05/12 21:36:15 sra Exp $ -->
26 <date>Jun 30, 2000</date>
30 <refentrytitle>lwres_gnba</refentrytitle>
31 <manvolnum>3</manvolnum>
32 <refmiscinfo>BIND9</refmiscinfo>
39 <holder>Internet Systems Consortium, Inc. ("ISC")</holder>
44 <holder>Internet Software Consortium.</holder>
49 <refname>lwres_gnbarequest_render</refname>
50 <refname>lwres_gnbaresponse_render</refname>
51 <refname>lwres_gnbarequest_parse</refname>
52 <refname>lwres_gnbaresponse_parse</refname>
53 <refname>lwres_gnbaresponse_free</refname>
54 <refname>lwres_gnbarequest_free</refname>
55 <refpurpose>lightweight resolver getnamebyaddress message handling</refpurpose>
62 #include <lwres/lwres.h>
68 <function>lwres_gnbarequest_render</function>
70 <paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>
71 <paramdef>lwres_gnbarequest_t *<parameter>req</parameter></paramdef>
72 <paramdef>lwres_lwpacket_t *<parameter>pkt</parameter></paramdef>
73 <paramdef>lwres_buffer_t *<parameter>b</parameter></paramdef>
79 <function>lwres_gnbaresponse_render</function>
81 <paramdef>lwres_context_t *ctx</paramdef>
82 <paramdef>lwres_gnbaresponse_t *req</paramdef>
83 <paramdef>lwres_lwpacket_t *pkt</paramdef>
84 <paramdef>lwres_buffer_t *b</paramdef>
89 <function>lwres_gnbarequest_parse</function></funcdef>
90 <paramdef>lwres_context_t *ctx</paramdef>
91 <paramdef>lwres_buffer_t *b</paramdef>
92 <paramdef>lwres_lwpacket_t *pkt</paramdef>
93 <paramdef>lwres_gnbarequest_t **structp</paramdef>
98 <function>lwres_gnbaresponse_parse</function></funcdef>
99 <paramdef>lwres_context_t *ctx</paramdef>
100 <paramdef>lwres_buffer_t *b</paramdef>
101 <paramdef>lwres_lwpacket_t *pkt</paramdef>
102 <paramdef>lwres_gnbaresponse_t **structp</paramdef>
108 <function>lwres_gnbaresponse_free</function>
110 <paramdef>lwres_context_t *ctx</paramdef>
111 <paramdef>lwres_gnbaresponse_t **structp</paramdef>
116 <function>lwres_gnbarequest_free</function></funcdef>
117 <paramdef>lwres_context_t *ctx</paramdef>
118 <paramdef>lwres_gnbarequest_t **structp</paramdef>
125 <title>DESCRIPTION</title>
127 These are low-level routines for creating and parsing
128 lightweight resolver address-to-name lookup request and
132 There are four main functions for the getnamebyaddr opcode.
133 One render function converts a getnamebyaddr request structure —
134 <type>lwres_gnbarequest_t</type> —
135 to the lightweight resolver's canonical format.
136 It is complemented by a parse function that converts a packet in this
137 canonical format to a getnamebyaddr request structure.
138 Another render function converts the getnamebyaddr response structure —
139 <type>lwres_gnbaresponse_t</type>
140 to the canonical format.
141 This is complemented by a parse function which converts a packet in
142 canonical format to a getnamebyaddr response structure.
145 These structures are defined in
146 <filename>lwres/lwres.h</filename>.
147 They are shown below.
149 #define LWRES_OPCODE_GETNAMEBYADDR 0x00010002U
152 lwres_uint32_t flags;
154 } lwres_gnbarequest_t;
157 lwres_uint32_t flags;
158 lwres_uint16_t naliases;
161 lwres_uint16_t realnamelen;
162 lwres_uint16_t *aliaslen;
165 } lwres_gnbaresponse_t;
169 <function>lwres_gnbarequest_render()</function>
170 uses resolver context
171 <varname>ctx</varname>
172 to convert getnamebyaddr request structure
173 <varname>req</varname>
175 The packet header structure
176 <varname>pkt</varname>
177 is initialised and transferred to
179 <varname>b</varname>.
181 <varname>*req</varname>
182 are then appended to the buffer in canonical format.
183 <function>lwres_gnbaresponse_render()</function>
184 performs the same task, except it converts a getnamebyaddr response structure
185 <type>lwres_gnbaresponse_t</type>
186 to the lightweight resolver's canonical format.
189 <function>lwres_gnbarequest_parse()</function>
191 <varname>ctx</varname>
192 to convert the contents of packet
193 <varname>pkt</varname>
195 <type>lwres_gnbarequest_t</type>
199 provides space to be used for storing this structure.
200 When the function succeeds, the resulting
201 <type>lwres_gnbarequest_t</type>
202 is made available through
203 <varname>*structp</varname>.
204 <function>lwres_gnbaresponse_parse()</function>
205 offers the same semantics as
206 <function>lwres_gnbarequest_parse()</function>
208 <type>lwres_gnbaresponse_t</type>
212 <function>lwres_gnbaresponse_free()</function>
214 <function>lwres_gnbarequest_free()</function>
215 release the memory in resolver context
216 <varname>ctx</varname>
217 that was allocated to the
218 <type>lwres_gnbaresponse_t</type>
220 <type>lwres_gnbarequest_t</type>
221 structures referenced via
222 <varname>structp</varname>.
223 Any memory associated with ancillary buffers and strings for those
224 structures is also discarded.
228 <title>RETURN VALUES</title>
230 The getnamebyaddr opcode functions
231 <function>lwres_gnbarequest_render()</function>,
232 <function>lwres_gnbaresponse_render()</function>
233 <function>lwres_gnbarequest_parse()</function>
235 <function>lwres_gnbaresponse_parse()</function>
237 <errorcode>LWRES_R_SUCCESS</errorcode>
240 <errorcode>LWRES_R_NOMEMORY</errorcode>
241 if memory allocation fails.
242 <errorcode>LWRES_R_UNEXPECTEDEND</errorcode>
243 is returned if the available space in the buffer
245 is too small to accommodate the packet header or the
246 <type>lwres_gnbarequest_t</type>
248 <type>lwres_gnbaresponse_t</type>
250 <function>lwres_gnbarequest_parse()</function>
252 <function>lwres_gnbaresponse_parse()</function>
254 <errorcode>LWRES_R_UNEXPECTEDEND</errorcode>
255 if the buffer is not empty after decoding the received packet.
256 These functions will return
257 <errorcode>LWRES_R_FAILURE</errorcode>
259 <structfield>pktflags</structfield>
260 in the packet header structure
261 <type>lwres_lwpacket_t</type>
262 indicate that the packet is not a response to an earlier query.
266 <title>SEE ALSO</title>
269 <refentrytitle>lwres_packet</refentrytitle>
270 <manvolnum>3</manvolnum>